Product Design & Insights

Some ideas are so fundamentally sound that once you’ve experienced them, you can’t go back.That’s exactly how I feel about Line Arrays. They’re not a gimmick or a fringe setup for a niche group of audiophiles—they’re a transformative way to experience sound. And, with the new Serie S lineup, we’ve made that experience more accessible, more elegant, and more powerful than ever before. Contents: What Is a Line Array? How Line Arrays Work New Serie S Line Array Models The Journey to Line Arrays Line Array Performance Delivery Line Array Setup Considerations Are Line Arrays for You?   What is a Line Array? In simple terms, a Line Array is a vertical stack of three identically matched REL subwoofers placed behind each main speaker. This configuration radically enhances dynamics, improves room coupling, and creates a vertical column of bass energy that supports the entire soundstage—not just the low end.  But here’s the key: it’s not just about more bass, it’s about dimensional bass—and a new dimension to the soundstage. The added height and depth create a holographic realism where instruments seem to float in three-dimensional space, vocals take on body and presence, and the boundaries of your room dissolve. Why it Works Traditional single-sub systems radiate bass from one point in the room. That’s fine—until it isn’t. The moment your room interacts poorly with those waves, things get messy. You’ll notice hotspots, dead zones, or a general lack of focus. Line Arrays solve that by distributing bass energy more evenly across the vertical plane. That means better integration with your main speakers, greater uniformity throughout the listening area, and a height and depth to the stage that no single subwoofer can replicate. We’re talking about holographic realism. Instruments float. Vocals gain weight. The room disappears. Serie S: Built for It Three of the new Serie S models are fully Line Array–capable: Carbon Special Black Label S/850 S/550 Each of these features consistent cabinet dimensions, stackable rail levelers, and isolation feet that allow for stable, secure multi-unit configurations. We designed these models with vertical setup in mind from day one. Their amplifiers, filters, and cabinets are tuned to perform in this kind of array, with zero compromises. Important note: Not every REL subwoofer is Line Array compatible. And even within a given Series, Line Arrays only work when models are matched. Our new Serie S/550 must be paired & assembled with Serie S/550, for example. Just to keep you in the loop here, our other Line Array compatible products are the Reference No.31, Reference No.32, and HT/1510 Predator. Building Over Time Not everyone begins with six subs. Many owners build their Line Array in stages—starting with a single pair, then adding a second tier, and eventually completing the full three-tier configuration as their system and listening ambitions grow. Each step offers audible improvements, allowing you to appreciate the journey while working toward the ultimate expression of Line Array performance. What You’ll Hear When properly set up, a Serie S Line Array delivers: Massively improved dynamics without harshness Heightened realism—especially in vocals and acoustic instruments Even bass response across the entire room A sense of air, depth, and vertical space that simply doesn’t exist in traditional subwoofer systems It’s hard to overstate the effect. You don’t just hear the performance, you’re part of it. Setup Considerations Line Arrays do require commitment: three subwoofers per side, matching cabling, careful calibration, and rail levelers. Rail levelers ensure each cabinet sits perfectly stable, which is crucial when assembling subwoofers into Line Arrays.  And for those wondering about wireless—yes, Airship Direct can be used in Line Array configurations if each column shares a receiver channel. For absolute top-tier results, however, we still recommend wired High Level Input wherever possible. If your system is at a place where you’re chasing ultimate realism, there’s simply no better upgrade. Who It's For If you’ve invested in high-performance speakers and amplification, and you're looking for that next-level jump in immersion and emotional connection, Line Arrays are for you.They’re not just louder, they’re dimensional, more lifelike, more consistent, and deeply satisfying. This is how we close the gap between reproduction and reality. —John  

At REL, we believe performance should be beautiful—and beauty should serve a purpose. With the new Serie S lineup, we’ve extended that philosophy beyond the cabinet and into the final detail: the grille. For this generation, we’re offering two grille options—our classic cloth grille, and for the first time ever in this category, an optional premium wood grille that redefines what a subwoofer can look like in a high-end interior.Let me walk you through these choices and the thinking behind them. The Cloth Grille: Timeless, Functional, and IncludedOur black cloth grille has long been a staple at REL. It’s clean, understated, and acoustically transparent. For the new Serie S, the cloth grille remains the standard inclusion on 212 Black Label, along with a black and white cloth grille for S/850 and S/550. It’s designed to disappear visually and sonically—just like the subwoofer itself. Whether you’re building a stealthy home theatre or a modern two-channel system, this grille gets out of the way, both visually and audibly. The Premium Wood Grille: Elevated CraftsmanshipThe big news is the new premium wood grille, is standard on the Carbon Special Black Label and optional on all other Serie S models. Crafted with attention to materiality and proportion, the premium wood grille is more than a cosmetic upgrade. It’s a design element that transforms the sub into a furniture-grade object—a piece that looks at home alongside fine cabinetry, media consoles, and mid-century modern furnishings. The curved slat design offers a sense of rhythm and airflow, echoing the precision and natural beauty of the sound it helps deliver. We designed it to complement the cabinet without overwhelming it. The result is warm, architectural, and quietly confident. Easy Swapping, Secure Fit Each grille—cloth or wood—uses a hidden magnetic mounting system for clean lines and secure placement. Swapping from one to the other is effortless, allowing customers to choose the look that best fits their space or evolve it over time. Why Offer Two? Because no two listening spaces—or listeners—are exactly alike. Some want their system to visually disappear, while others want it to become part of the story. With the new Serie S grille system, you can now choose. As for performance, both grille types have been voiced into the design, ensuring that what you see never compromises what you hear.  For us, that’s non-negotiable. Which One is Right for You? Cloth grille: standard, minimalist, and ideal for hidden setups. Premium Wood grille: expressive, architectural, and perfect for design-forward spaces. If you’re buying a Carbon Special Black Label, you’ll receive the premium wood grille by default. If you’re purchasing a 212 Black Label, S/850, or S/550, you’ll receive the cloth grille—but have the option to upgrade to wood for an additional charge. And let me just say—it’s worth it. Because when your subwoofer looks this good and sounds even better, that’s REL at its best. —John

This article shares the brief and colorful (groan) journey REL has taken to produce two gorgeous new finishes in our Special Edition versions of the T/9x. Last year, we reintroduced a red that for legal and political reasons we call Italian Racing Red. People who own cars with a prancing horse on their flanks will recognize it as Rosso Forza and yes, the brand starts with an “F” and ends with an “I”. This year, we’re pushing the boundaries of color even further with the introduction of two bold new shades: a striking yellow and a fiery orange. But these aren’t just any colors; they’re the result of a meticulous process inspired by some of the most legendary cars on the planet. Let’s face it – color is irresistible. It’s what draws us in, captivates us, and keeps us coming back for more. Just like how 4K pulls you into its vibrant world, our new T/9x colors are designed to grab your attention and never let go. No one knows this better than the billionaires who run F-1 Racing. For sheer retina-sizzling punch, the color schemes that are applied to each car’s body are designed to do one thing and one thing only: grab hold of your eyeballs and keep them fixed on their car. But it wasn’t always so. Ferrari’s racing red used to look more like burgundy. Here’s a picture of that color reissued in the late 90’s. When we decided to expand our palette to include a gorgeous and fresh yellow and a deep, richly-hued orange, we looked to exotic cars and race teams for inspiration. Why not, the work that goes into creating a unique hue for the world’s greatest cars runs into the millions. So, were we able to simply grab McLaren’s Orange in a rattle can and spray our subs? Believe me, there were days I wished we could. Just as with the subtle Grey T/9x, applying bright colors to a relatively modest-sized subwoofer like our T/9x requires careful scaling of the color in question. A color that looks incredible on a Lamborghini may not work on a subwoofer barely over one cubic foot (.0283 cubic meters) in size. We know, we tried. And we tried. And we tried about 20 more times. What works when applying paint to such a small object, is to interpret the color and intensity so that it reads correctly on the object. Take our Tangerine Dream orange color. We started out shooting samples in Porsche’s GT-3RS orange. Impossible to get the correct formula. The NSA doesn’t keep secrets as well as Porsche when it comes to this rare shade. So, we sprayed cabinet samples in McLaren’s Orange (over the years, there have been about 15 variations of what you may think is “McClaren Orange”).  Didn’t cut it. We shot versions using Porsche’s “standard” orange as used on, among other things, their 2008 Boxster Special Edition. For some reason, the way light struck the surface, it looked as though a vanilla milkshake had fallen into the paint can. So, we mixed a custom color we call Tangerine Dream, a half shade deeper than P-car’s orange, and a little brighter than McOrange. Unique, maybe a tiny bit like the 2008-12 Fire Orange M3 but with the flame banked a tiny bit. We could have called it REL Orange, but somehow Tangerine Dream better fits its personality. Then we turned to our fresh-as-Spring Yellow. By now, we had discarded trying to reuse anything directly from a factory. Same drill though, you think it’s going to be easy, and the more you think that, the more you’ll struggle. So, we went straight into the “We want the vividness of the C-6 Corvette Velocity Yellow, but without the “why did I leave my sunglasses home today” effect that color has. Also, it looked terrible in real living rooms. So, custom color matching again and we arrived at a wonderful yellow, a yellow so pretty that the first 6 women we showed it to all said (pretty much instantly) “I want to buy that!” I’m going to say that again v-e-r-r-y slowly… six women agreed on a color instantly. Without any prodding. Do you know how much money Dupont, PPG, Sikkens, and every other paint company would pay to get that reaction? Then we had to give it a name. With apologies to the Automobile Club de l’Oust who sanctioned the famous 24 Hours of Le Mans, I hit on the only name it could possibly be. Le Mon Yellow, to bring it back to high-performance cars that inspire us. Of course, being a part of our Special Edition mini-series of T/9x’s we had to apply the full monte, so on went the triple chrome plated cast and machined solid billet feet. We use triple chrome plating; triple refers to the old-fashioned, more expensive method for chroming. We use pure copper, with nickel plating on top of the copper, and then finish with an extra-long bath in chromium to leave a deep lustrous chrome. Yes, it costs more. Yes, it looks about 100 times better than doing it the slapdash way. And, of course, all our drivers in the SE range are that next step beyond the standard T/x drivers. The use of 6000 series carbon fibre in the center cap produces incredible  stiffness yet reduces moving mass significantly. This alone is enough to add an extra 1.2 dB, not a huge increase in output, but a significant indicator that the amp is not having to work as hard to produce the same output, which means that it plays even louder than a standard T/9x. Look at it this way, the custom paint alone costs more than the $150 we charge for any of the SEs (last check red ran $735/gallon) the orange and yellow are within a stone’s throw of that. We  add the extra performance of the carbon fibre for free because we wanted there to be an audible improvement, not just a color upgrade. Thanks for riding along on this colorful adventure with us. Every time we push the boundaries—whether it’s through performance or design—we do it with one goal in mind: to bring you closer to the perfect sound experience. And with these Special Edition T/9x subs, we think we’ve done just that. Thank you for reading our latest blog. We strive to provide content that’s both entertaining and educational. If you have questions or suggestions for future articles, reach out to us at contactus@rel.net. We value your input and will do our best to respond within a few days. With over 160 years of combined experience, we’re committed to making your audio experience exceptional. If you found value in this piece, please share it with friends who might benefit.

When someone of Steve Guttenberg’s stature recommends our Classic 98 as "for $1499 you're not gonna get an amplifier that does it like this does... this is going to deliver more of a sonic upgrade than any other component you can buy for $1499," one tends to take that seriously as a design team.     So, what did we do? We set about building Classic 99. Yeah, we’re gluttons for punishment.   The brief was clear from the start—not always the case at the outset of a new project. Sometimes, it takes a more meandering journey as various options are explored. In this case, we knew the clear and obvious path to making Classic 98 better. Note I didn’t say “Make it bigger so it will play louder (it does) or go lower (it also does that).” I specifically said making it better. A bigger, better driver and tons more power were staring us right in the face. Not because they play louder and go deeper, but because with the right tuning, we felt we could bring out more nuance, more emotional involvement, more air in the soundstage, and clarity in the critical upper-midrange-to-low-treble region that is a sticky issue in many high-end systems.   Better, because REL means making every sonic cue more completely and fully realized, and even though the new Classic 99 is a beast when used in home theatre, we always voice using revealing 2-channel cuts. They’re not our favorite music, these are cuts we’ve learned to trust over the years that reveal some “tell” in a development prototype that leads us to improve seemingly minor aspects. But, once we get those “minor” issues resolved, it allows us to unlock more dramatic improvements. We call these hang nails. A professional pitcher in baseball (presumably also true of a world-class cricket bowler) may be able to throw 100 mph, but if a tiny blister or sore spot develops on the index finger of his throwing hand, he has to come out of the game. His accuracy will suffer and not only is it insanely dangerous to have a wild pitcher throwing 100 mph, his game will go to hell with balls spraying the dirt around the catcher. Not good.   So, we first set about creating the new 12” hand-thrown paper center cap—these take 24 hours to create a twelve cone versus hot pressed, flat paper stock that can be produced at the rate of several hundred a day. The center cap is not only responsible for the stiffness in the structure of the cone, but it’s also most responsible for texture and delineation in the reproduction of music, so it is always something that needs special attention. At 12” in diameter instead of 10” we would have 45% more surface area to work with, meaning that pressurization of the room would be easily achieved. And, while we wouldn’t need it, our geometry allowed for an extra inch (25mm) of fore and aft travel. Which is a lot more output.     We pressed into service one of our 500-watt Class D amplifiers, then limited it to 450 watts (which was probably 100 watts more than we needed) to deliver greater impact and that sense of effortlessness that wonderful big amps often possess. Then we fine-tuned the PerfectFilter™ in our filter set to take the best advantage of all this largesse, including a cabinet that is some 40% larger in internal volume than Classic 98 offers. And it all came together with just a few tweaks and generational improvements over a 6-month cycle.   And we had it…or so we thought. But something was missing. Classic 99 was seductive out of the box. Precisely because when a big, confident subwoofer strides deep bass into the room, it is easy to be seduced by the whole bigger/deeper/louder thing. When a subwoofer goes bigger/deeper/louder it’s easy to conclude that it’s “better”. But we didn’t sign off on it.   What was missing was the last bit of what we started off saying we were going to get. Delicacy, air, openness. When you hear it, it’s instantly identifiable as right, in the way that live music has “it”. Old Quad electrostats have it. Quad 63s don’t (sorry guys). Martin Logan CLS have it, Apogee Duetta Signatures have it, and it’s far easier to gain this clarity and graded nuance in stand-mounted speakers than in bigger floorstanders.   So, one night I got out a stack of my business cards. They happen to be exactly 1mm thick. I carefully added one card layer at a time (4) underneath the feet until the thickness we were hearing disappeared and at 5 business cards worth of shims (5mm) the sound was perfect. So, I called our CAD genius Ryan and asked him to add 6mm. Why 6? Because sometimes we’re all idiots. What difference could 1mm make? A LOT as it turned out.  A couple of weeks later, we got the (wrong) 6mm taller feet in, bolted them on, and…they sucked. No truly. We had lost all the weight and body our new design had in spades. Panicked, I sent an email to our metal factory asking for a set at the 5mm increase to be built as fast as possible.   Nervously, we sat down to listen, and whew! The relief we felt when, after 10 minutes, we swapped out the too-tall 6mm versions for the 5mm ones and we had the best of both worlds. The fine-tuning of a larger slot to relieve the build-up of pressure on the bottom was exactly what we needed. Turning this from something most people would have been happy with (I guarantee you no competitor is listening at this level of criticality) to a design that we believe will be seen as important, as really special is why we do this. It’s why I hoped twenty years ago when our team started this journey, that we could put out meaningful designs, that would add to the discourse in this wonderful hobby of ours.   We give you Classic 99. We do so proudly. This REL is special, it is meaningful and powerful and makes an utterly beautiful sound. And, it will pound the hell out of most rooms without breaking a sweat. Classic 99, the beautiful beast that we fell in love with along the journey.   Enjoy!       Thank you for reading our latest blog. We strive to provide content that’s both entertaining and educational.   If you have questions or suggestions for future articles, reach out to us at contactus@rel.net. We value your input and will do our best to respond within a few days.   With over 160 years of combined experience, we’re committed to making your audio experience exceptional. If you found value in this piece, please share it with friends who might benefit.